1. Field of the Invention
The present invention deals with a handheld cartridge filling apparatus for filling the cartridge with vaccines or other fluids, and in particular to a hand-operable cartridge filling apparatus for use with needle-free ampules or cartridges and the associated filling station when dealing with multiple cartridges in a magazine.
2. Description of Prior Art
The specification of U.S. Patent Publication US 2003/0040715A1, filed Aug. 20, 2002, and corresponding PCT Publication WO 03/015846 A2, filed Aug. 21, 2002, herein incorporated by reference, describes several methods for filling ampules or cartridges prior to their use with a needle-free injection system. In particular, FIG. 19 of the foregoing earlier publications illustrate a filling station that uses a transfer syringe which first extracts the diluent from a vial supplied by the manufacturer. The syringe then transfers the diluent into a second vial containing lyophilized (powdered) vaccine. After the mixing of the diluent and the vaccine is completed, the transfer system extracts the vaccine or other medication from the vial supplied by the manufacturer. The transfer syringe containing the mixed vaccine is then placed into a described filling station and the vaccine therein is progressively transferred from the syringe into the orifice, or distal end of the empty ampules or cartridges. This filling procedure is accomplished with a simple repetitive motion of a lever which incrementally advances the syringe plunger with a positive force to move the vaccine out of the syringe and into the cartridge. Conversely, in this disclosure, suction or negative pressure is used to pull the plunger into the syringe as fluid is evacuated. Also mentioned in the preceding patent publications is the possibility of filling through the orifice end of the cartridge by pressurizing fluid in the vial to fill the cartridge without the use of a transfer syringe. It was stated in the specification of the foregoing publications, that “the main difficulty in using the vial without first transferring to the syringe, comes in the valving required to control flow of air into the vial and flow of injectate out of the vial”. However, the simplified and inexpensive method of valving and pressure control as discussed in this disclosure is applied to a hand-held apparatus that houses the vial directly, and is then used to fill the ampules through the orifice end. During the development, it was realized that the handheld apparatus for transferring vaccine to the cartridges can also be used in the filling station with either the syringe or vial inserted, and is especially useful for filling multiple cartridges in a magazine format. With regard to vaccine transfer with the handheld device, neither the valving as described herein, nor the handheld device being used in the filling station option was illustrated in the earlier application.